RESEARCH, EDUCATION & MEDICINE
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F R O M T H E M E D I C A L L I N E
58
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WINTER 2014
Ear Equalization
with Hoods
DAN medics answer your questions about dive medicine.
Q:
If I am not wearing a hood I have
no problems equalizing my ears.
When I wear a hood I always have
great difficulty. Why the difference?
A:
When we pressurize the middle-ear
space using a Valsalva maneuver
or other equalization technique,
the tympanic membrane (ear drum) bulges
outward slightly. If the ear canal is uncovered
and can transmit that pressure, the water
in the ear canal moves easily in response. A
hood that fits snugly against the outer ear can
greatly restrict the movement of this water,
hampering the diver’s ability to equalize.
One of the easiest remedies to this is
to insert a finger under the hood near the
ear, which will allow the water to move more easily.
Another solution some divers choose to implement is
to cut a hole from the inside of the hood, near the ear
canal, through the inner lining and the neoprene but
leaving the outer fabric or covering intact. The hole
allows the water to move with little restriction.
— Marty McCafferty, EMT-P, DMT
Q:
In a few weeks I’ll be doing my first dive
trip on a liveaboard. Several friends of
mine who are veterans of liveaboards
suggested I use a sleep medication (zolpidem or
zopiclone), since travel and the environment can
disrupt normal sleep patterns. I would like to use
them so as not to be sleep deprived, but how safe
are they in a context of frequent diving?
A:
Both medications have been shown to be less
problematic for most individuals than other
hypnotics or sedatives. However, they are not
without risk. There is evidence both from clinical trials
and field reports that misuse of these medications can
impair one’s ability to safely drive a car. The physical
and cognitive skills required for diving are very similar
to the demands of driving, so it is reasonable to draw a
parallel between the two activities. To reduce the risk of
impairment, it is essential to take either medication as
directed. The medication should be taken just prior to
retiring for a night of eight hours of uninterrupted sleep.
Time-zone changes may affect circadian rhythms, and
employing measures to adjust will help sleep disturbances.
Many divers find the active environment extremely
conducive to sleep and are pleasantly surprised at their
ability to sleep well at the end of a busy dive day.
It is important to discuss the use of these medications
with your doctor to determine if they are appropriate
for you, especially if you are taking other medications
or have medical conditions such as sleep apnea. It is
equally important to try the medication well in advance
of your dive trip to assess its effects and any potential
impairment in a safe and familiar environment.
Another important factor to consider is that one of the
medications you mentioned requires less time than the
other for the body to eliminate. This does not preclude
the use of either, but depending on your sensitivity the
shorter-acting medication may be a prudent choice. In
STEPHEN FRINK
